Define OutputStreamTaskListener & close BufferedBuildListener

src/main/java/org/jenkinsci/plugins/workflow/log/BufferedBuildListener.java

@@ -28,27 +28,38 @@
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import hudson.CloseProofOutputStream;
 import hudson.model.BuildListener;
+import hudson.remoting.Channel;
+import hudson.remoting.ChannelClosedException;
 import hudson.remoting.RemoteOutputStream;
 import hudson.util.StreamTaskListener;
 import java.io.Closeable;
+import java.io.FilterOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.Logger;
 import org.jenkinsci.remoting.SerializableOnlyOverRemoting;
 
 /**
  * Unlike {@link StreamTaskListener} this does not set {@code autoflush} on the reconstructed {@link PrintStream}.
  * It also wraps on the remote side in {@link DelayBufferedOutputStream}.
  */
-final class BufferedBuildListener implements BuildListener, Closeable, SerializableOnlyOverRemoting {
+final class BufferedBuildListener implements BuildListener, Closeable, SerializableOnlyOverRemoting, OutputStreamTaskListener {
+
+    private static final Logger LOGGER = Logger.getLogger(BufferedBuildListener.class.getName());
 
     private final OutputStream out;
     @SuppressFBWarnings(value = "SE_BAD_FIELD", justification = "using Replacement anyway, fields here are irrelevant")
     private final PrintStream ps;
 
-    BufferedBuildListener(OutputStream out) throws IOException {
+    BufferedBuildListener(OutputStream out) {
         this.out = out;
-        ps = new PrintStream(out, false, "UTF-8");
+        ps = new PrintStream(out, false, StandardCharsets.UTF_8);
+    }
+
+    @Override public OutputStream getOutputStream() {
+        return out;
     }
 
     @NonNull
@@ -75,8 +86,59 @@ private static final class Replacement implements SerializableOnlyOverRemoting {
             this.ros = new RemoteOutputStream(new CloseProofOutputStream(cbl.out));
         }
 
-        private Object readResolve() throws IOException {
-            return new BufferedBuildListener(new GCFlushedOutputStream(new DelayBufferedOutputStream(ros, tuning)));
+        private Object readResolve() {
+            var cos = new CloseableOutputStream(new GCFlushedOutputStream(new DelayBufferedOutputStream(ros, tuning)));
+            Channel.currentOrFail().addListener(new Channel.Listener() {
+                @Override public void onClosed(Channel channel, IOException cause) {
+                    LOGGER.fine(() -> "closing " + channel.getName());
+                    cos.close(channel, cause);
+                }
+            });
+            return new BufferedBuildListener(cos);
+        }
+
+    }
+
+    /**
+     * Output stream which throws {@link ChannelClosedException} when appropriate.
+     * Otherwise callers could continue trying to write to {@link DelayBufferedOutputStream}
+     * long after {@link Channel#isClosingOrClosed} without errors.
+     * In the case of {@code org.jenkinsci.plugins.durabletask.Handler.output},
+     * this is actively harmful since it would mean that writes apparently succeed
+     * and {@code last-location.txt} would move forward even though output was lost.
+     */
+    private static final class CloseableOutputStream extends FilterOutputStream {
+
+        /** non-null if closed */
+        private Channel channel;
+        /** optional close cause */
+        private IOException cause;
+
+        CloseableOutputStream(OutputStream delegate) {
+            super(delegate);
+        }
+
+        void close(Channel channel, IOException cause) {
+            this.channel = channel;
+            this.cause = cause;
+            // Do not call close(): ProxyOutputStream.doClose would just throw ChannelClosedException: …: channel is already closed
+        }
+
+        private void checkClosed() throws IOException {
+            if (channel != null) {
+                throw new ChannelClosedException(channel, cause);
+            }
+            LOGGER.finer("not closed yet");
+        }
+
+        @Override public void write(int b) throws IOException {
+            checkClosed();
+            out.write(b);
+        }
+
+        @Override public void write(byte[] b, int off, int len) throws IOException {
+            checkClosed();
+            out.write(b, off, len);
         }
 
     }

src/main/java/org/jenkinsci/plugins/workflow/log/OutputStreamTaskListener.java

@@ -0,0 +1,100 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2023 CloudBees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package org.jenkinsci.plugins.workflow.log;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import hudson.model.TaskListener;
+import java.io.FilterOutputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.lang.reflect.Field;
+import java.lang.reflect.InaccessibleObjectException;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import org.apache.commons.io.output.ClosedOutputStream;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.Beta;
+
+/**
+ * {@link TaskListener} which can directly return an {@link OutputStream} not wrapped in a {@link PrintStream}.
+ * This is important for logging since the error-swallowing behavior of {@link PrintStream} is unwanted,
+ * and {@link PrintStream#checkError} is useless.
+ * <p>{@link #getLogger} should generally be implemented in terms of {@link #getOutputStream}
+ * (no autoflush, using {@link StandardCharsets#UTF_8})
+ * but there is not a {@code default} implementation since the result should be cached in a field.
+ */
+@Restricted(Beta.class)
+public interface OutputStreamTaskListener extends TaskListener {
+
+    /**
+     * Returns the {@link OutputStream} from which {@link #getLogger} was constructed.
+     */
+    @NonNull OutputStream getOutputStream();
+
+    /**
+     * Tries to call {@link #getOutputStream} and otherwise falls back to reflective access to {@link PrintStream#out} when possible, at worst returning the {@link PrintStream} itself.
+     */
+    static @NonNull OutputStream getOutputStream(@NonNull TaskListener listener) {
+        if (listener instanceof OutputStreamTaskListener) {
+            return ((OutputStreamTaskListener) listener).getOutputStream();
+        }
+        PrintStream ps = listener.getLogger();
+        if (ps.getClass() != PrintStream.class) {
+            Logger.getLogger(OutputStreamTaskListener.class.getName()).warning(() -> "Unexpected PrintStream subclass " + ps.getClass().getName() + " which might override write(…); error handling is degraded unless OutputStreamTaskListener is used: " + listener.getClass().getName());
+            return ps;
+        }
+        if (Runtime.version().compareToIgnoreOptional(Runtime.Version.parse("17")) >= 0) {
+            Logger.getLogger(OutputStreamTaskListener.class.getName()).warning(() -> "On Java 17+ error handling is degraded unless OutputStreamTaskListener is used: " + listener.getClass().getName());
+            return ps;
+        }
+        Field printStreamDelegate;
+        try {
+            printStreamDelegate = FilterOutputStream.class.getDeclaredField("out");
+        } catch (NoSuchFieldException x) {
+            Logger.getLogger(OutputStreamTaskListener.class.getName()).log(Level.WARNING, "PrintStream.out defined in Java Platform and protected, so should not happen.", x);
+            return ps;
+        }
+        try {
+            printStreamDelegate.setAccessible(true);
+        } catch (InaccessibleObjectException x) {
+            Logger.getLogger(OutputStreamTaskListener.class.getName()).warning(() -> "Using --illegal-access=deny? Error handling is degraded unless OutputStreamTaskListener is used: " + listener.getClass().getName());
+            return ps;
+        }
+        OutputStream os;
+        try {
+            os = (OutputStream) printStreamDelegate.get(ps);
+        } catch (IllegalAccessException x) {
+            Logger.getLogger(OutputStreamTaskListener.class.getName()).log(Level.WARNING, "Unexpected failure to access PrintStream.out", x);
+            return ps;
+        }
+        if (os == null) {
+            // like PrintStream.ensureOpen
+            return ClosedOutputStream.CLOSED_OUTPUT_STREAM;
+        }
+        return os;
+    }
+
+}

src/main/java/org/jenkinsci/plugins/workflow/log/TaskListenerDecorator.java

@@ -37,7 +37,6 @@
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.io.Serializable;
-import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -237,7 +236,7 @@ private static OutputStream decorateAll(OutputStream base, List<TaskListenerDeco
         return base;
     }
 
-    private static final class DecoratedTaskListener implements BuildListener {
+    private static final class DecoratedTaskListener implements BuildListener, OutputStreamTaskListener {
 
         private static final long serialVersionUID = 1;
 
@@ -253,6 +252,7 @@ private static final class DecoratedTaskListener implements BuildListener {
          */
         private final @NonNull List<TaskListenerDecorator> decorators;
 
+        private transient OutputStream out;
         private transient PrintStream logger;
 
         DecoratedTaskListener(@NonNull TaskListener delegate, @NonNull List<TaskListenerDecorator> decorators) {
@@ -262,14 +262,18 @@ private static final class DecoratedTaskListener implements BuildListener {
             this.decorators = decorators;
         }
 
+        @NonNull
+        @Override public OutputStream getOutputStream() {
+            if (out == null) {
+                out = decorateAll(OutputStreamTaskListener.getOutputStream(delegate), decorators);
+            }
+            return out;
+        }
+
         @NonNull
         @Override public PrintStream getLogger() {
             if (logger == null) {
-                try {
-                    logger = new PrintStream(decorateAll(delegate.getLogger(), decorators), false, "UTF-8");
-                } catch (UnsupportedEncodingException x) {
-                    throw new AssertionError(x);
-                }
+                logger = new PrintStream(getOutputStream(), false, StandardCharsets.UTF_8);
             }
             return logger;
         }
@@ -280,7 +284,7 @@ private static final class DecoratedTaskListener implements BuildListener {
 
     }
 
-    private static final class CloseableTaskListener implements BuildListener, AutoCloseable {
+    private static final class CloseableTaskListener implements BuildListener, AutoCloseable, OutputStreamTaskListener {
 
         static BuildListener of(BuildListener mainDelegate, TaskListener closeDelegate) {
             if (closeDelegate instanceof AutoCloseable) {
@@ -301,6 +305,12 @@ private CloseableTaskListener(@NonNull TaskListener mainDelegate, @NonNull TaskL
             assert closeDelegate instanceof AutoCloseable;
         }
 
+        @NonNull
+        @Override
+        public OutputStream getOutputStream() {
+            return OutputStreamTaskListener.getOutputStream(mainDelegate);
+        }
+
         @NonNull
         @Override public PrintStream getLogger() {
             return mainDelegate.getLogger();